Multi-Spectral Image Sensor Filter Layout for Accurate Color Detection
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Solution Overview
Problem
Conventional image sensors with RGB filters have limited color representation accuracy due to the classification of wavelength bands into only three sections, which affects object recognition and image quality, especially under varying ambient light conditions.
Innovation Solution
An image sensor design incorporating a light filter with a color filter and multi-spectral filters arranged adjacent to and coplanar with a CMOS device, where the multi-spectral filters include multiple band filters transmitting light in narrower wavelength bands, allowing for more precise light detection and ambient light calibration to optimize color matrix correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional RGB color filter is used to classify wavelength bands into three sections, then the device complexity is low and ease of manufacture is high, but the color representation accuracy and object recognition performance deteriorate
Solution Approach 1:
The patent divides the wavelength band into multiple narrow sections using multiple bandpass filters with different central wavelengths (e.g., 430nm, 480nm, 530nm, 580nm, 630nm). Each bandpass filter segment captures a specific wavelength range, enabling detailed spectral analysis and improved color representation accuracy beyond the conventional three-color RGB system.
Solution Approach 2:
The image sensor is designed to perform multiple functions: it can operate in a first mode using only the color filter for standard color imaging, and in a second mode using both the color filter and multi-spectral filters for enhanced spectral analysis. This multi-functionality allows the system to adapt to different application requirements without requiring a completely separate device.
2Measurement precision
If multiple bandpass filters are integrated to improve spectral resolution, then the color representation accuracy improves, but the manufacturing precision requirements and device complexity increase
Solution Approach 1:
The patent combines the color filter and multi-spectral filters into a single integrated light filter structure that is disposed over the pixel array. This unified structure reduces the number of separate components and simplifies the manufacturing process, thereby lowering the cumulative alignment precision requirements compared to stacking multiple separate filter layers.
Solution Approach 2:
Different regions of the light filter are designed with different spectral transmission characteristics. The color filter regions provide broad spectral coverage for standard imaging, while the multi-spectral filter regions provide narrowband spectral selection for enhanced analysis. This local differentiation allows each region to be optimized for its specific function while maintaining overall system manufacturability.
3Measurement precision
If multi-spectral filters with narrower wavelength bands are used, then the object recognition performance improves, but the light intensity reaching the detector decreases
Solution Approach 1:
The patent enables dynamic switching between different operational modes. In a first mode, the system uses only the color filter to maximize light intensity for standard imaging. In a second mode, the system activates the multi-spectral filters for enhanced spectral analysis and object recognition when sufficient light is available. This dynamic adaptability allows the system to optimize between light intensity and spectral resolution based on lighting conditions and application requirements.
Solution Approach 2:
The system can selectively activate only certain bandpass filters based on the imaging requirements and ambient light conditions. When full spectral analysis is not needed, fewer filters are activated to maintain higher light intensity. This partial action approach allows the system to achieve improved object recognition performance only when necessary, rather than always using all narrowband filters.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances color representation accuracy and object recognition by providing a clearer and higher resolution image through the use of multi-spectral filters that transmit light in narrower wavelength bands, improving image quality under different lighting conditions.
Implementation Method 1
each of the plurality of band filters may be configured to transmit light in a band filter wavelength range that is narrower than a wavelength range of the plurality of red filters, the plurality of green filters and the plurality of blue filters
Implementation Method 2
a light detector that includes a plurality of pixels disposed on a lower portion of the light filter, the light detector being configured to detect light transmitted through the light filter
Data Source
AI summary
An image sensor includes: a light filter; and a light detector that includes a plurality of pixels disposed on a lower portion of the light filter, the light detector being configured to detect light transmitted through the light filter. The light filter includes: a color filter that includes a plurality of red filters, a plurality of green filters, and a plurality of blue filters. The light filter includes: a plurality of multi-spectral filters disposed adjacent to and coplanar with the color filter, each of the plurality of multispectral filters including a plurality of band filters configured to transmit light in different wavelength bands. Each of the plurality of band filters is configured to transmit light in a band filter wavelength range that is narrower than a wavelength range of the plurality of red filters, the plurality of green filters and the plurality of blue filters.